Hardware restart / KVM caused it?

[Wizzard1]

Dont know if there are many techies here, but I have a system wheich, when switched to on my KVM occasionaly, restarts. It's not the power supply or the OS, as it has doen it in XP and in Memtest86. Memtest86 reports no errors, left on over the weekend.... But as soon as I switch from it, and then back to it, it restarts.

I am thinking keyboard/mouse/io conflict... Maybe BIOS flash, maybe replace motherboard... The client reported no such malfunction before it was here. What do you guys think?